According to a source who would have reason to know, the fourth-generation iPod touch is changing back shapes—sorry, readers who have been posting with love for the dome-like curved iPod touch 2G/3G back, but that’s going away. And it’s not going to be glass like the iPhone 4, for all of you folks who were fearing accidental shatters like the ones we’ve heard Apple Stores are continuing to see on a daily basis. The new shape is…

Familiar. Think of the top of a MacBook Pro, only smaller, which is to say flat rather than curved at the center—closer to the look of the first-generation iPod touch’s back, only with modifications. The rear camera is there, but there is still some question as to whether what’s next to it will be a LED flash like the one in the iPhone 4, or a microphone like the one next to the video camera of the iPod nano. We’ve been told to expect a microphone rather than a flash, with a continuation of the bottom-mounted headphone port and Dock Connector port.

And we’re continuing to hear from sources that the little touchscreen device—the one with the sub-2-inch screen—is being thought of as a nano rather than a shuffle, even though it doesn’t make much sense to us. We’ll know more soon enough.